| 摘要 |
PROBLEM TO BE SOLVED: To obtain a power supply device which enables high precesion measurement, without being influenced by switching noise produced by ON's/OFF's of a step-up circuit, when a necessary step-up level is almost a limit. SOLUTION: A power supply device for a battery driven apparatus has a detection unit 13 which detects a power supply voltage. The voltage of a power supply 11 can be stepped up by a step-up unit 12 to at least a 1st step-up voltage or to a 2nd step-up voltage higher than the 1st one. If the power supply voltage detected by the detection unit 13 is within the predetermined range from the 1st step-up voltage, a changeover unit 15 which changes the output voltage is made to operate with a control unit 14, and the 2nd step-up voltage is outputted to the step-up unit 12. |
